The objectives of this proposal are: first, to establish reliable human methodology to quantify and correlate antral pressure responses and gastric emptying of solids and liquids. Secondly, to characterize the physiological role of solid particle size, relative volume of solids and liquids in the stomach, and the presence of nutrients, on pressure-emptying relationships. Thirdly, to apply the above techniques and concepts to the study of pathophysiological responses in disease. A prototype for this approach will be the investigation of mechanisms involved in gastric stasis of solids in type I gastric ulcer. Methods involve intubation/perfusion and the use of nonabsorbable markers for different physical and chemical components of a normal meal. The principal investigator is well acquainted with these methods, many of which have gradually evolved from work performed in his laboratory over the past several years. Significant developments in this area will be: a) the use of miniature strain-gauge transducers to measure pressure events in conjunction with the emptying of meals, and b) the employment of small enteric-coated PEG spheres of different sizes as a standardized analog for dietary solid particles. To be emphasized is the fact that there are no adequate animal models for most common gastrointestinal disorders including those affecting the stomach. The human methodology and studies proposed can help provide a link between current experimental data and the elucidation of abnormal mechanisms involved in human disease.